چکیده:
The purpose of this study was to examine cardiovascular and respiratory changes in students carrying backpacks. 15 male students (age: 12.5±0.5 years old; height: 164.7±1.8 cm; and weight: 55±1.6 kg) volunteered to participate in this study. All subjects randomly carried backpacks of 0%، 8%، 10.5% and 13% of their own body weight in different days on treadmill at 3.9 km/h for 15 minutes. Heart rate (HR)، pulmonary ventilation (VE) and frequency respiration (FR) of the subjects were measured by Gas Analyzer System and SBP and DBP were measured by a digital blood pressure meter in 3 positions: test، exercise (15th minute) and recovery (3 minutes after walking). The statistical analysis of data indicated that SBP، DBP and VE in 10.5% and 13% load conditions were significantly higher than in 0% and 8% load conditions (P=0.000). Also، 10.5% and 13% load conditions were significantly higher 3 minutes after walking when compared to the rest level (P=0.000). There were no significant differences between 0% and 8% load conditions in both during and 3 minutes after walking conditions. HR and FR of subjects showed no significant difference during and after carrying different loads. According to the results of the present study، carrying backpacks equal to 8% of body weight does not create any significant changes in cardio-respiratory parameters of students، thus it can be recommended as an optimal weight of backpack for students.
خلاصه ماشینی:
Based on the results of the present study, carrying a backpack equivalent to 8% of body weight does not create significant changes in the respiratory and cardiovascular parameters of students.
In this regard and to answer these questions, this research has attempted to study and investigate the effects of carrying backpacks with different weights on some cardiovascular and respiratory variables of students aged 12 to 13 years using laboratory methods.
Results and Findings of the Research The mean and standard deviation of individual characteristics of the subjects including age, weight, height, IMB, backpack weight, and relative backpack weight are presented in Table 1, and the mean and standard deviation of the values of each physiological variable in rest, activity, and recovery states in different load carrying tests are presented in Table 2.
5 and 13% body weight load conditions was still significantly higher than baseline resting values 3 minutes after carrying (P There was no significant difference in recovery (P>5%), however, the 10.
(Refer to the page image) (Refer to the page image) (Refer to the page image) Discussion and Conclusion The present research, comparing PBS and PBD of subjects under different backpack loading conditions, showed that the amount of these variables significantly increased during backpack carrying with relative weights equivalent to 5.
(1)- gnoH Comparing the heart rate of subjects between different backpack carrying tests showed that the amount of this variable increased when carrying backpacks with different weights, but there was no significant difference in the amount of this increase between different loading conditions.
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